Aqueous defoamants



AQUEOUS DEFOA John S. Bradley V, Pitman, and John J. Giammaria,

Woodbury, N. L, assignors to Socony Mobil Oil Company, Inc., acorporation of New York No Drawing. Application January 14, 1953, SerialNo. 331,326

6 Claims. (Cl. 252358) This invention relates to antifoam agents. It ismore particularly concerned with the inhibition of foam in aqueoussystems.

As is known to those familiar with the art, the .occurrence of foamingin aqueous systems gives rise to severe industrial problems. Thus, inaqueous systems, such as are encountered in paper, glue, fermentationand like industries, foaming during agitation makes for difficulty inhandling the processes; and even decreases efliciencies and yields.

It has now been found that foaming in aqueous systems can be inhibitedby a simple and economical method. It has been discovered that by theaddition of certain phosphonic or phosphinic acids, esters and salts toaqueous systems, in small amounts, foaming thereof is greatly reduced.

Accordingly, it is an object of this invention to provide a method forinhibiting foaming in aqueous systems. Another object is to provideaqueous systems having reduced foaming tendencies. A specific object isto provide aqueous systems, which are prone to foam, containing minoramounts of a phosphorus compound of the class; phosphonate esters, saltsof phosphonate mcnoesters, phosphinic acids, or salts of phosphinicacids. Another specific object is to provide a method for reducingfoaming tendencies in an aqueous system, which comprises adding theretoone or more of the aforementioned phosphorus compounds. Other objectsand advantages of this invention Will become apparent to those skilledin the art, from the following detailed description.

The present invention provides an aqueous system subject to foamingcontaining a small amount, sufficient to reduce the foaming thereof, ofat least one phosphoruscontaining compound selected from the groupconsisting of (A) a compound having the formula wherein R is a radicalselected from the group consisting of an alkyl radical, a trihalomethylradical, a cyclo- Patented May '14, 1.9.57

alkyl radical, a terpenyl radical, an aralkyl radical, and an arylradical; R is a lower alkyl radical; and M is a radical selected fromthe group consisting of an alkali metal and R; and (B) a compound havingthe formula wherein R" is a radical'selected from the group consistingof an alkyl radical and a carboxyalkyl radical, and M is a radicalselected from the group consisting of a hydrogen atom and an alkalimetal.

The defoamants utilizable in the present invention are in the generalclass of phosphinic and phosphonic acids, and their derivatives. Onlyspecific members of this class are ntilizable, however, as is discussedhereinafter.

One group of additives contemplated can be represented by the formulawherein R is an alkyl radical, a trihalomethyl radical, a cycloalkylradical, a terpenyl radical, an aralkyl radical, or an aryl radical; R"is a lower alkyl radical; and M is an alkali metal or R. In the aboveformula, it is preferred that R contain between about 1 carbon atom andabout 24 carbon atoms and, more preferably, between about 6 carbon atomsand about 10 carbon atoms. The lower alkyl radicals, R, contain betweenone carbon atom and 5 carbon atoms. The alkali metals, of course, arethose of group I of the periodic chart of the elements. Sodium andpotassium are preferred.

As will be apparent from the formula, the compounds contemplated therebyare diesters of phosphonic acids and alkali-metal salts of monoesters ofphosphonic acids. Non-limiting examples of these compounds, in additionto those of the working examples, are diethyl ethanephosphonate,di-t-butyl pentanephosphonate, dipropyl hexanephosphonate, dimethylpentane-3-phosphonate, diisoamyl methylcyclohexanephosphonate, dipropyltetracosanephosphonate, dimethyl phenylbutanephosphonate, dibutylnaphthylethanephosphonate, diisopropyl naphthalenephosphonate, sodiummonopropyl hexanephosphonate, lithium monoethyl ethanephosphonate,potassium monoamyl pentanephosphonate, rubidium monopropylhexanephosphonate, sodium monomethyl pentane-3-phosphonate, potassiummonobutyl methylcyclohexanephosphonate, sodium monoisopropyltetracosanephosphonate, potassium monomethyl phenylbutanephosphonate,lithium monobutyl naphthylethanephosphonate, and sodium mono-t-butylnaphthalenephosphonate.

I The other class of phosphorus compounds contemplated herein isrepresented by the formula R" OM wherein R is an alkyl radical or acarboxyl-substituted alkyl radical (i. e., one derived from a fattyacid), and M is hydrogen or an alkali metal. It is preferred that R"contain between about 3 carbon atoms and about 20 carbon atoms.

It will be noted from the formula that this class of compounds includedialkylphosphinic acids and their alkali metal salts. anddi(carboxyalkyl) phosphinic acids and their alkali metal salts.Non-limiting examples thereof are dipropylphosphinic acid, sodiumdipropylphosphinate, diisoamylphosphinic acid, potassiumdiisoheptylphosphinate, di(2-ethylhexyl)phospbinic acid, lithiumdinonylphosphinate, didecylphosphinic acid,'rubidiumdidodecylphosphinate, di(carboxyethyl)phosphinic acid, sodium di(carboxyamyl phosphinate, di (carboxydecyl) phosphinic acid, potassiumdi(carboxytridecyl)phosphinate, di(carboxypentadecyl)phosphinic acid,sodium di(carboxyheptadecyl)phosphinate, etc.

Various methods are known to the art for producing the phosphoruscompounds utilized in this invention. Thus, phosphonic acids have beenproduced by reacting a hydrocarbon with phosphorus trichloride (U. S.Patent No. 2,137,792). Esters have been made by reacting sodium salts ofphosphites with organic halides (U. S. Patent No. 2,397,422). A novelmethod for producing the phosphorus compounds is to react a phosphoruscompound having hydrogen on phosphorus with an unsaturated compoundunder free-radical conditions, as disclosed in co-pending applicationSerial No. 107,376, filed July 28, 1949. See also additional prior artprocesses set forth in that application. It must be understood, however,that the method of preparing these phosphorus compounds does not affectthis invention. Any phosphorus compounds having the structures set forthhereinbefore are elfective, regardless of how they are prepared.

It is also within the purview of this invention to use combinations ofthe aforediscussed phosphorous compounds. In general preferred practice,two phosphorous compounds will be used in equal parts by weight, i. e.,in a 50-50 mixture. It must be understood, however, that otherproportions in the mixture can be used, as low as a few percent, byweight, of one component of the mixture. Thus, mixtures, such as 2-98,-90, 40-60, etc. are within the scope of this invention. Mixtures ofdialkyl alkanephosphonates and sodium dialkylphosphinate areparticularly effective.

The effectiveness of the phosphorus compounds, or mixtures thereof, willvary somewhat in different aqueous systems. The choice of a singlesuitable compound or mixture can be established readily by testing in agiven system. The concentration of defoamant used will vary betweenabout 0.001 percent and about 1.0 percent, by weight, based upon theweight of the aqueous system. In preferred practice, satisfactoryreduction of foaming tendencies is achieved with an additiveconcentration of between about 0.001 percent and about 0.1 percent, byweight.

The defoamants can be added to the aqueous system directly, or in theform of dispersions or solutions. In either event, the concentrationsdefined hereinbefore refer to actual concentration of phosphoruscompounds exclusive of the solvent or dispersant. It is to be noted thatthe solvents or dispersants themselves exert no defoaming action.Suitable solvents or dispersants are water, ethanol, butanol, dioxane,benzene, toluene, xylene, etc.

The following specific working examples are for the I Each blend wassubjected to the foam test.

purpose of illustrating the defoamant compositions of this invention. Itmust be strictly understood that this invention is not to be limited tothe particular defoamants, systems, or concentrations used in theexamples. Those skilled in the art will appreciate that a wide varietyof other compositions can be used, as described hereinbefore.

The foaming test utilized herein is similar to that described by C. W.Foulk and J. N. Miller in Ind. Eng. Chem., 23, 1283 (1931). Theapparatus consists of a 1.5-liter graduated cylinder, the base of whichconsists of a sintered glass disc which is connected to an air lineregulated to deliver air at the rate of milliliters per minute. Inconducting the test, air is blown through a l00-milliliter sample of theaqueous system, for 10 minutes. At the end of this period, the volume offoam is noted. The defoamant, when used, is added to the surface of theaqueous system. The volume of foam is reported as the dilference betweenthe foam level and the liquid level.

In all of the examples, except Example 14, a 0.05 weight percent aqueoussolution of saponin was used as the foamant aqueous system. In Example14, however, the saponin solution was adjusted to a pH of 4.3, in orderto approximate an acidic foamant system.

EXAMPLES 1 THROUGH 13 Various diakyl phosphonates were added to samplesof the 0.05-percent saponin solution, both with and without dispersants(solvents). Each blend was subjected to the foam test. Pertinent data onthe compositions and test results are set forth in Table I.

EXAMPLE 14 A portion of the saponin solution was buffered to pH 4.3 withpotassium acid phthalate. This solution gave 920 milliliters of foam inthe foam test. Then 0.05 percent, by weight, of dibutyloctane-Z-phosphonate was added to the acidic solution. The amount offoam then given in the foam test was only 2 milliliters.

EXAMPLES 15 THROUGH 17 Various alkali-metal monoalkyl phosphonates wereadded to portions of the 0.05-percent saponin solution, usingdispersants. Each blend was subjected to the foam test. Pertinent dataon the compositions and test results are set forth in Table I.

V EXAMPLES 18 AND 19 Various phosphinic acids were added to portions ofthe 0.05-percent saponin solution, using dispersants. Pertinent data onthe compositions and test results are set forth in Table I.

EXAMPLES 20 AND 21 EXAMPLES 22 AND 23 Various 50-50 mixtures ofphosphonate esters and alkali-metal phosphinate or phosphonate saltswere added to portions of the 0.05-percent saponin solution, usingdispersants. Each blend was subjected to the foam test. Pertinent dataon the compositions and test results are set forth in Table I.

Although the present invention has been described in conjunction withpreferred embodiments, it is to be understood that modifications andvariations may be resorted to, without departing from the spirit andscope of this invention, as those skilled in the are will readilyunderstand. Such variations and modifications are considered to bewithin the purview and scope of the appended claims.

aeeasaa Table I.-F0am tests in 0.05% aqueous sapom'n solutionsPhosphorus Compound do Dibugyi isooctanephosphonatc o Dibugylisononanephosphonate 0 Diethlyl n-do ecane o Dibutyln-octadecanephosphonate. Dibutyl C alkanephosphonate L. Dibugylcyclohexanephosphonate. o Dibutyl pinanephosphonate Dlbugylphenylmethanephosphonate o Dibutyltrlchioromethanephosphonate Diallylbenzenephosphonate Na rronobutyl octane-2-phosphonatc Na monobutyl G20alkanephosphonate Na monobutyl C24 alkanephosphonateG)Dioctadecylphosphinic acid Di (carboxyheptadecane) phosphinic with Nadipentadecylphosphinate( Na dioctadecylphosphinateDibutyloctane-Z-phosphonate, 50-50 mixture. Na di octadecyl phosphinate,50-50 mixture 0 Dibutyl octane-2-phosphonate, 50-50 mixture... Namonobutyl Oi; alkanephosphonate, 50-50 mixture.

Concn., M1. foam Wt. Icr- Dispox-sant i at 10 cent min.

None..- n-butanQL...

( Concentration oi phosphorus compound. Dlspersant not included.

( Compounds were prepared What is claimed is:

1. An aqueous system subject to foaming containing a small amount,suflicient to reduce the foaming thereof, of at least onephosphorus-containing compound selected from the group consisting of (A)a compound having the formula wherein R is a radical selected from thegroup consisting of an alkyl radical, a trihalomethyl radical, acycloalkyl radical, a terpenyl radical, an aralkyl radical, and an arylradical; R is a lower alkyl radical; and M is a radical selected fromthe group consisting of an alkali metal and R; and (B) a compound havingthe formula wherein R" is a radical selected from the group consistingof an alkyl radical and a carboxyalkyl radical, and M is a radicalselected from the group consisting of a hydrogen atom and an alkalimetal.

2. An aqueous system subject to foam containing between about 0.001percent, by weight, and about 1 percent, by weight, of dibutyloctane-2-ph0sph0nate.

from oleflns obtained from wax cracking.

3. An aqueous system subject to foam containing between about 0.001percent, by weight, and about 1 percent, by weight, of dibutylcyclohexanephosphonate.

4. An aqueous system subject to foam containing between about 0.001percent, by weight, and about 1 percent, by weight, of dibutyltriehloromethanephosphonate.

5. An aqueous system subject to foam containing between about 0.001percent, by weight, and about 1 percent, by weight, of sodium monobutyloctane-2- phosphonate.

6. An aqueous system subject to foam containing between about 0.001percent, by weight, and about 1 percent, by weight, of a 50-50 mixtureby weightof dibutyl octane-Z-phosphonate and sodiumdioctadecylphosphinate.

References Cited in the file of this patent UNITED STATES PATENTS

1. AN AQUEOUS SYSTEM SUBJECT TO FOAMING CONTAINING A SMALL AMOUNT,SUFFICIENT TO REDUCE THE FOAMING THEREOF, OF AT LEAST ONEPHOSPHORUS-CONTAINING COMPOUND SELECTED FROM THE GROUP CONSISTING OF (A)A COMPOUND HAVING THE FORMULA